1. Field of the Invention
This invention relates to aqueous cosmetic and pharmaceutical preparations as well as additives therefor.
2. Description of the Prior Art
Aqueous preparations of active ingredients are frequently used in pharmaceutics and especially in cosmetics. For reasons related to the application or use of the preparations, it may be desirable that the preparations have an increased viscosity and exist in the form of gels or pastes.
Typical examples of such cosmetic preparations are highly viscous or gel-like shampoos as well as bath and shower gels. Besides active cosmetic ingredients, these products contain surfactants, especially anionic surfactants, such as, for example, alkylbenzene sulfonates and alkyl ether sulfates. Also, in recent years, betaines have been used to an increasing extent as surfactants.
Until now, anionic or cationic, synthetic polymers or vegetable thickening agents have been used to thicken such preparations. It is however a disadvantage of these known thickening agents that they cannot be universally employed, but are system-specific and frequently produce cloudiness and form deposits. Such products are especially unsuitable for thickening aqueous betaine solutions.
Salts, such as, for example, sodium chloride, have been added to anionic surfactants. This addition is ineffective with sulfosuccinic esters and betaines. Moreover, in larger quantities, the added mineral salts have a salting out effect on the dissolved surfactants and detract from the ability of such solutions to have a solubilizing effect.
Polyethyleneglycol derivatives which act as thickeners are disclosed in German Offenlegungsschrift No. 31 40 160. These compounds correspond to the general formula: ##STR3## in which R represents an alkyl radical and/or an alkoxymethyl radical or a mixture of these radicals;
n represents an average group number of 20 to 500 and, preferably, of 30 to 200, and PA0 x and y represent average group numbers of 0 to 8, the sum (x+y) varying between 1 and 8.
These compounds are synthesized by adding long chain 1,2-alkylene oxides, such as, for example, 1,2-octadecene oxides or alkyl glycidyl ethers, such as, for example oleyl glycidyl or alkenyl glycidyl ethers, to polyethylene glycols.
The compounds of the above-mentioned Offenlegungsschrift are relatively expensive because of the long-chain epoxides used. Moreover, their thickening capability and especially their solubilizing capability are not always adequate.